1. Field of Invention
The present invention relates to methods of operating laser systems and more particularly to methods for operating a gas laser with dual species.
2. Description of the Prior Art
In their paper entitled Chemical Lasers From The Reactions Of ClF And ClF.sub.3 With H.sub.2 And CH.sub.4 : A Possible Chain Branching Chemical Laser, the Journal of Chemical Physics, Vol. 56, No. 2, Jan. 15, 1972, pages 969-975, O. D. Krogh et al., describe various laser systems based on the atomic fluorine reactions. Various elements when subjected to flash photolysis provide the fluorine required in such systems, however, the source materials involved are highly reactive and difficult to control. Also, the flash photolysis technique for providing the atomic fluorine limits the operation of such systems fo a pulsed output. Alternatively, pulsed discharge or glow discharge techniques have been used to provide the atomic fluorine and provide laser emission from hydrogen fluoride and hydrogen chloride. As a practical matter, such discharge systems include various operating limitations such as the production of undesired chemical species by the electric discharges, the requirement for an external source of electrical power and an inability to produce a continuous wave output.
U.S. Pat. No. 3,818,374 entitled Chain Reaction HCL Chemical Laser, issued to George Emmanuel on June 18, 1974, teaches a chemical laser having a continuous wave output which is chemically driven thereby avoiding the need for an external source of electrical power as in Krogh et al. In the Emmanuel device, fluorine, chlorine and hydrogen are mixed in a chamber wherein the fluorine and hydrogen react chemically, producing heat thereby causing some of the chlorine to dissociate into atoms. The combustion products are expanded and admixed with hydrogen which in turn reacts with the atomic chlorine, producing hydrogen chloride and atomic hydrogen. Subsequently, the atomic hydrogen reacts with the molecular chlorine forming both excited hydrogen chloride which lases, and additional atomic chlorine which is free to react with the molecular hydrogen and continue the chain reaction. The wavelength of the output beam is characteristic of either the hydrogen chloride or deuterium chloride molecule depending upon whether hydrogen or deuterium is admixed with the supersonic stream of chlorine.
J. R. Airey discloses a chemical laser requiring no external energy source for operation in U.S. Pat. No. 3,560,876 entitled Supersonic Flow Gaseous Chemical Laser which issued on Feb. 2, 1971. In essence, hydrogen and chlorine are reacted and the heat of combustion is used to dissociate molecular fluorine. Then the atomic fluorine is mixed with the products of combustion which include hydrogen chloride, permitting the substitution reaction wherein fluorine replaces the chlorine to form excited hydrogen fluoride which provides the source of laser output radiation.
In U.S. Pat. No. 3,701,045 issued Oct. 24, 1972 and entitled Chemical Mixing Laser, Bronfin et al describe a chemical laser wherein two primary reactants under combustion produce free atoms which are subsequently combined with secondary reactants to produce a single lasing species such as HF or HCL. The system requires no external energy source and does operate on a continuous wave basis.